The present invention relates to nucleic acid sequences encoding Ostertagia ostertagi proteins and to parts of such nucleic acid sequences that encode an immunogenic fragment of such proteins, and to DNA fragments, recombinant DNA molecules, live recombinant carriers and host cells comprising such nucleic acid sequences or such parts thereof. The invention also relates to Ostertagia ostertagi proteins and immunogenic parts thereof encoded by such sequences. Furthermore, the present invention relates to vaccines comprising such nucleic acid sequences and parts thereof, DNA fragments, recombinant DNA molecules, live recombinant carriers and host cells comprising such nucleic acid sequences or such parts thereof, proteins or immunogenic parts thereof and antibodies against such proteins or immunogenic parts thereof. Also, the invention relates to the use of said proteins in vaccines and for the manufacture of vaccines. Moreover, the invention relates to the use of said nucleic acid sequences, proteins or antibodies for diagnostic or vaccination purposes. Finally the invention relates to diagnostic kits comprising such nucleic acids, proteins or antibodies against such proteins.

Description of the Invention

REFERENCE TO SEQUENCE LISTING

The material saved as "text document" under the file name "SubstituteSequenceListing" created on Sep. 9, 2008 is hereby incorporated by reference.

The present invention relates to nucleic acid sequences encoding Ostertagia ostertagi proteins, to parts of such nucleic acid sequences that encode an immunogenic fragment of such proteins, to DNA fragments, recombinant DNA molecules, live recombinant carriers and host cells comprising such nucleic acid sequences or such parts thereof. The invention also relates to Ostertagia ostertagi proteins and immunogenic parts thereof encoded by such sequences. Furthermore, the present invention relates to vaccines comprising such nucleic acid sequences and parts thereof, DNA fragments, recombinant DNA molecules, live recombinant carriers and host cells comprising such nucleic acid sequences or such parts thereof, proteins or immunogenic parts thereof and antibodies against such proteins or immunogenic parts thereof. Also, the invention relates to the use of said proteins in vaccines and for the manufacture of vaccines. Moreover, the invention relates to the use of said nucleic acid sequences, proteins or antibodies for diagnostic or vaccination purposes. Finally the invention relates to diagnostic kits comprising such nucleic acids, proteins or antibodies against such proteins.

There are about 82 million cattle in the EU and about 97 million in the USA most of which are exposed to infection with gastro-intestinal nematodes at grazing, with resultant, often substantial, impaired production efficiency. The most common and most pathogenic of these nematodes is Ostertagia ostertagi, which infects the abomasum of cattle. The disease syndrome caused by gastrointestinal nematodes, commonly referred to as parasitic gastro-enteritis (PGE), drastically diminishes the economic viability of cattle production units (Kloosterman, A. et al., Parasitology Today 8, 330-335 (1992); Vercruysse, J. and Claerebout, E., Veterinary Parasitology 98, 195-214 (2001)). The animals most at risk for PGE are calves during their first grazing season. Clinical PGE in grazing calves is characterized by (watery) diarrhea, weight loss, a dull hair coat, anorexia, a general loss of condition and eventually death (Anderson, N. et al., Veterinary Record 41, 196-204 (1965); Hilderson, H. et al., Vlaams Diergeneeskundig Tidschrift 56, 269-29 (1987)). However, production losses are mainly due to sub-clinical infections, with no overt signs of disease. Substantial reductions in daily weight gain are observed in untreated first grazing season calves with sub-clinical infections (Shaw D. J., et al., Vetenary Parasitology 75, 115-131 (1998). Adult cows can still harbor large numbers of O. ostertagi (e.g. Borgsteede, F. H. M., et al., Veterinary Parasitology 89, 287-296 (2000); Agneessens, J. et al., Veterinary Parasitology 90, 83-92 (2000)). Although gastrointestinal nematode infections in adult cows are usually sub clinical, they are associated with decreased levels of milk production (Gross, S. J. et al., Veterinary Record 144, 581-587 (1999)). Carcass quality is also affected by gastrointestinal nematode infections, with reduced carcass weight, killing out percentage and related carcass measurements (Entrocasso, C. M. et al., Research in Veterinary Science 40, 76-85 (1986)). Control of PGE in Europe is based almost exclusively on the use of anthelmintic drugs (Vercruysse, J. and Dorny, P., International Journal for Parasitology 29, 165-175 (1999)). However, the increased use of anthelmintics in cattle over the past two decades (Borgsteede, F. H. M. et al., Veterinary Parasitoogy 78, 2336 (1998); Schnieder, T. et al., Veterinary Record 145, 704-706 (1999); Claerebout, E. et al., Vlaams Diergeneeskundig Tijdschrift 69, 108-115 (2000)) has several drawbacks. The high costs of anthelmintic treatments, the negative effect of preventive anthelmintic treatments on the development of natural immunity against gastrointestinal nematodes (Vercruysse, J. et al., Parasitology Today 10, 129-132 (1994); Claerebout, E. and Vercruysse J., Le Point Veterinaire (Numero special) 28, 175-179 (1997)), consumer concerns regarding drug residues in food products and in the environment (Wall, R. and Strong, L., Nature 327, 418-421 (1987); Steel, J. W. In: NRA Special Review of Macrocyclic Lactones, National Registration Authority for Agricultural and Veterinary Chemicals, Canberra (1998); Strong, L., Veterinary Parasitology 48, 3-17 (1993)) and, last but not least, the increasing incidence of parasite resistance against the available anthelmintics (Vermunt, J. J., et al., Veterinary Record 137, 43-45 (1995); Vermunt, J. J. et al., New Zealand Veterinary Journal 44, 188-193 (1996); Coles, G. C. et al., Veterinary Record 142, 255-256 (1998); Gill, J. H. and Lacey, E., International Journal for Parasitology 28, 863-877 (1998); and Fiel, C. A. et al., Revista de Medicina Veterinaria (Buenos Aires) 81, 310-315 (2000)) are strong incentives for the producers to adopt alternative control systems (Vercruysse & Dorny (1999), supra). Vaccination is being considered as the most feasible solution (Knox, D. P., Parasitology 120, S43-S61 (2000)).

However, despite the evolution in biotechnology that allows the development of `new generation` vaccines based on recombinant DNA technology, no vaccines against gastrointestinal nematode parasites are available until now. The main problems that hamper the development of nematode vaccines in ruminants are (1) most parasite antigens that have been selected for vaccine development are `hidden antigens`, i.e. antigens that are not recognized by the host during a natural infection. Consequently, the immune response that is generated by vaccination with these antigens is not boosted by a natural re-infection; (2) recombinant nematode proteins inducing a protective immune response have so far not been found.

It is an objective of the present invention to provide polypeptides that are capable of contributing to protection against the pathogenic effects of Ostertagia ostertagi infection in cattle.

It was now surprisingly found that 7 different polypeptides could be specifically identified and isolated, each of these different polypeptides being capable of inducing an immune response against Ostertagia parasites.

The inventors have found that these polypeptides can be used, either alone or in combination with each other, as vaccine components to provide a vaccine, which indeed contributes to the protection against Ostertagia ostertagi infection in cattle and helps to decrease the damage caused by Ostertagia ostertagi.

Three different approaches have been used for the detection of the genes encoding the vaccine components according to the invention. One approach, presented in detail under Example 1, uses specifically prepared anti-excretory-secretory protein rabbit antiserum for the detection of genes encoding immunoreactive Ostertagia ostertagi proteins. This approach has led to the finding of five novel immunogenic proteins for which the coding sequences are depicted in SEQ ID NO: 1, 3, 5, 7 and 9 as given below.

The gene encoding one such protein has now been cloned and sequenced and a nucleic acid sequence of the gene that comprises immunogenic determinants is depicted in SEQ ID NO: 7 The full-length gene encodes a protein of about 1600 amino acids (as partially depicted in SEQ ID NO: 8) with a molecular mass of >=200 kD.

It is well known in the art, that many different nucleic add sequences can encode one and the same protein. This phenomenon is commonly known as wobble in the second and especially the third base of each triplet encoding an amino acid. This phenomenon can result in a heterology for two nucleic acid sequences still encoding the same protein. Therefore, in principle, two nucleic add sequences having a sequence homology as low as 70% can still encode one and the same protein.

Thus, one form of a first embodiment of the present invention relates to a nucleic acid sequence encoding an Ostertagia ostertagi protein or a part of said nucleic acid sequence that encodes an immunogenic fragment of said protein wherein said nucleic acid sequence or said part thereof has at least 85% homology with the nucleic acid sequence of the Ostertagia ostertragi protein gene as depicted in SEQ ID NO: 7

The concept of immunogenic fragments is defined below. The length of a nucleic acid sequence encoding an immunogenic fragment is usually at least 21 nucleotides, but preferably 24, 27, 30, 33 or even 36 nucleotides.

The molecular weight of all proteins according to the invention is determined in gel electrophoresis on a polyacrylamide gel. Due to slight variability of molecular weight determination frequently encountered in the art the molecular weight can vary. Therefore the molecular weight of the proteins according to the invention should be interpreted as to be its theoretical molecular weight +/-5 kD.

Preferably, a nucleic acid sequence according to the invention encoding this Ostertagia ostertagi protein or a part of that nucleic acid sequence that encodes an immunogenic fragment of that protein has at least 90%, preferably 93%, more preferably 95% homology with the nucleic acid sequence of the Ostertagia ostertagi protein gene as depicted in SEQ ID NO: 7

Even more preferred is a homology level of 98%, 99% or even 100%.

The level of nucleotide homology can be determined with the computer program "BLAST 2 SEQUENCES" by selecting subprogram: "BLASTN" that can be found at www.ncbl.nim.nih.gov/blast/bl2seg/bl2.html.

A reference for this program is Tatiana A. Tatusova, Thomas L. Madden, FEMS Microbiol Letters 174, 247-250 (1999). Parameters used are the default parameters:

Reward for a match: +1. Penalty for a mismatch: -2. Open gap: 5. Extension gap: 2. Gap x_dropoff: 50.

Nucleotide sequences that are complementary to the sequence depicted in SEQ ID NO: 1, 3, 5, 7, 9, 11 or 13, described herein, or nucleotide sequences that comprise tandem arrays of the sequences according to the invention, are also within the scope of the invention.

Another form of this embodiment relates to a nucleic acid sequence encoding a 28 kD Ostertagia ostertagi protein or a part of said nucleic acid sequence that encodes an immunogenic fragment of said protein wherein said nucleic acid sequence or said part thereof has at least 85% homology with the nucleic acid sequence of the Ostertagia ostertagi protein gene as depicted in SEQ ID NO: 3.

Preferably, a nucleic acid sequence according to the invention encoding this Ostertagia ostertagi protein or a part of that nucleic acid sequence that encodes an immunogenic fragment of that protein has at least 90%, preferably 93%, more preferably 95% homology with the nucleic acid sequence of the Ostertagia ostertagi protein gene as depicted in SEQ ID NO: 3.

Even more preferred is a homology level of 98%, 99% or even 100%.

Still another form of this embodiment relates to a nucleic acid sequence encoding a 25 kD Ostertagia ostertagi protein or a part of said nucleic acid sequence that encodes an immunogenic fragment of said protein wherein said nucleic acid sequence or said part thereof has at least 85% homology with the nucleic acid sequence of the Ostertagia ostertagi protein gene as depicted in SEQ ID NO: 5.

Preferably, a nucleic acid sequence according to the invention encoding this Ostertagia ostertagi protein or a part of that nucleic acid sequence that encodes an immunogenic fragment of that protein has at least 90%, preferably 93%, more preferably 95% homology with the nucleic acid sequence of the Ostertagia ostertagi protein gene as depicted in SEQ ID NO: 5.

Even more preferred is a homology level of 98%, 99% or even 100%.

Again another form of this embodiment relates to a nucleic acid sequence encoding a 31 kD Ostertagia ostertagi protein or a part of said nucleic acid sequence that encodes an immunogenic fragment of said protein wherein said nucleic acid sequence or said part thereof has at least 85% homology with the nucleic acid sequence of the Ostertagia ostertagi protein gene as depicted in SEQ ID NO: 1.

Preferably, a nucleic acid sequence according to the invention encoding this 31 kD Ostertagia ostertagi protein or a part of that nucleic add sequence that encodes an immunogenic fragment of that protein has at least 90%, preferably 93%, more preferably 95% homology with the nucleic acid sequence of the Ostertagia ostertagi protein gene as depicted in SEQ ID NO: 1.

Even more preferred is a homology level of 98%, 99% or even 100%.

Another form of this embodiment relates to a nucleic acid sequence encoding a 30 kD Ostertagia ostertagi protein or a part of said nucleic acid sequence that encodes an immunogenic fragment of said protein wherein said nucleic add sequence or said part thereof has at least 85% homology with the nucleic add sequence of the 30 kD Ostertagia ostertagi protein gene as depicted in SEQ ID NO: 9.

Preferably, a nucleic acid sequence according to the invention encoding this 30 kD Ostertagia ostertagi protein or a part of that nucleic add sequence that encodes an immunogenic fragment of that protein has at least 90%, preferably 93%, more preferably 95% homology with the nucleic acid sequence of the Ostertagia ostertagi protein gene as depicted in SEQ ID NO: 9.

Even more preferred is a homology level of 98%, 99% or even 100%.

A second approach for the detection of vaccine components, presented in detail under Example 2, relied upon the analysis of components in a specific fraction of the parasite, the ES-fraction (excretory-secretory fraction) that play a role in establishing immunity against Ostertagia osterfagi. This approach surprisingly led to the finding of the 31 and 30 kD proteins described above (SEQ ID NO: 1 and 9). This provided a full confirmation of the importance of the 31 and 30 kD proteins described above as vaccine components.

A third approach for the detection of vaccine components, presented in detail under Example 3, uses local antibodies obtained from mucus and Antibody Secreting Cell (ASC) culture supernatant. Although serum antibodies can in principle be used to screen for candidate nematode antigens, local antibody responses produced at restricted tissue sites are not always detectable in serum. In addition, the persistence of serum antibodies makes it difficult to differentiate between previous and recent exposures to a pathogen. In contrast, local antibodies from the abomasal draining lymph nodes and from the mucus covering the abomasal mucosa are more specific for antigens present in the infected tissue at the time of examination. It was shown in studies in rats and sheep that cell cultures, containing antibody secreting cells (ASC) induced in vivo in lymph nodes draining the infected tissues, produce antibodies (ASC-probes) in the culture supernatant that specifically reflect the antigen exposure of the draining area and that stage-specific antigens are detected more readily by lymph node ASC-probes than by serum antibodies. Not only the draining lymph nodes but also the covering mucus-layer from the abomasum are a source of local antibodies. After challenge infection of calves with O. ostertagi, a negative correlation between fecundity of the worm and parasite specific IgA in the mucus was observed (Claerebout, E. et al., 17.sup.th International Conference of the World Association for the Advancement of Veterinary Parasitology, Copenhagen, 1999). cDNA libraries of the 3 different parasitic stages were screened with the same antibody probes to identify the nucleotide sequences that code for these antigens.

Details on the isolation of the genes encoding these antigens, and characterization of the protein antigens are presented in Examples 4 and 5.

This highly specific approach has been used for the selection of proteins and genes encoding these proteins that can be directly linked to immune status instead of mere infected status. This approach has surprisingly revealed two more immunogenic proteins, for which the coding sequences are depicted below under SEQ ID NO: 11 and 13.

Therefore, another form of this embodiment relates to a nucleic acid sequence encoding a 24 kD Ostertagia ostertagi protein or a part of said nucleic acid sequence that encodes an immunogenic fragment of said protein wherein said nucleic acid sequence or said part thereof has at least 85% homology with the nucleic acid sequence of the Ostertagia ostertagi protein gene as depicted in SEQ ID NO: 1.

Preferably, a nucleic acid sequence according to the invention encoding this Ostertagia ostertagi protein or a part of that nucleic acid sequence that encodes an immunogenic fragment of that protein has at least 90%, preferably 93%, more preferably 95% homology with the nucleic acid sequence of the 24 kD Ostertagia ostertagi protein gene as depicted in SEQ ID NO: 11.

Even more preferred is a homology level of 98%, 99% or even 100%.

Again another form of this embodiment relates to a nucleic acid sequence encoding a 65 kD Ostertagia ostertagi protein or a part of said nucleic acid sequence that encodes an immunogenic fragment of said protein wherein said nucleic acid sequence or said part thereof has at least 85% homology with the nucleic acid sequence of the Ostertagia ostertagi protein gene as depicted in SEQ ID NO: 13.

Preferably, a nucleic acid sequence according to the invention encoding this Ostertagia ostertagi protein or a part of that nucleic acid sequence that encodes an immunogenic fragment of that protein has at least 90%, preferably 93%, more preferably 95% homology with the nucleic acid sequence of the Ostertagia ostertagi protein gene as depicted in SEQ ID NO: 13.

Even more preferred is a homology level of 98%, 99% or even 100%.

Since the present invention discloses nucleic acid sequences encoding novel Ostertagia ostertagi proteins, it is now for the first time possible to obtain these proteins in sufficient quantities. This can e.g. be done by using expression systems to express the whole or parts of the genes encoding the proteins or immunogenic fragments thereof according to the invention.

Therefore, in a more preferred form of this embodiment, the invention relates to DNA fragments comprising a nucleic acid sequence according to the invention. A DNA fragment is a stretch of nucleotides that functions as a carrier for a nucleic acid sequence according to the invention. Such DNA fragments can e.g. be plasmids, into which a nucleic acid sequence according to the invention is cloned. Such DNA fragments are e.g. useful for enhancing the amount of DNA for use as a primer and for expression of a nucleic acid sequence according to the invention, as described below.

An essential requirement for the expression of the nucleic acid sequence is an adequate promoter functionally linked to the nucleic add sequence, so that the nucleic acid sequence is under the control of the promoter. It is obvious to those skilled in the art that the choice of a promoter extends to any eukaryotic, prokaryotic or viral promoter capable of directing gene transcription in cells used as host cells for protein expression. Therefore, an even more preferred form of this embodiment relates to a recombinant DNA molecule comprising a DNA fragment and/or a nucleic acid sequence according to the invention wherein the nucleic acid sequence according to the invention is placed under the control of a functionally linked promoter. This can be obtained by means of e.g. standard molecular biology techniques, e.g. Sambrook & Russell: "Molecular cloning: a laboratory manual" (2001), Cold Spring Harbor Laboratory Press; ISBN: 0879695773.

Functionally linked promoters are promoters that are capable of controlling the transcription of the nucleic acid sequences to which they are linked.

Such a promoter can be the native promoter of a novel gene according to the invention or another promoter of Ostertagia ostertagi, provided that that promoter is functional in the cells used for expression. It can also be a heterologous promoter. When the host cells are bacteria, useful expression control sequences, which may be used, include the Trp promoter and operator (Goeddel, et al., Nucl. Acids Res., 8, 4057 (1980)); the lac promoter and operator (Chang, et al., Nature, 275, 615 (1978)); the outer membrane protein promoter (Nakamura, K. and Inouge, M., EMBO J., 1, 771-775 (1982)); the bacteriophage lambda promoters and operators (Remaut, E. et al., Nucl. Acids Res., 11, 4677-4688 (1983)): the .alpha.-amylase (B. subtilis) promoter and operator, termination sequences and other expression enhancement and control sequences compatible with the selected host cell.

When the host cell is yeast, useful expression control sequences include, e.g., .alpha.-mating factor. For insect cells the polyhedrin or p10 promoters of baculoviruses can be used (Smith, G. E. et al., Mol. Cell. Biol. 3, 2156-2165 (1983)). When the host cell is of vertebrate origin illustrative useful expression control sequences include the (human) cytomegalovirus immediate early promoter (Seed, B. et al., Nature 329, 840-842 (1987); Fynan, E. F. et al., PNAS USA 90, 11478-11482 (1993); Ulmer, J. B. et al., Science 259, 1745-1748 (1993)), Rous sarcoma virus LTR (RSV), Gorman, C. M. et al., PNAS USA 79, 6777-6781 (1982); Fynan et al., supra; Ulmer et al., supra), the MPSV LTR (Stacey et al., J. Virology 50, 725-732 (1984)), SV40 immediate early promoter (Sprague J. et al., J. Virology 451 773 (1983)), the SV-40 promoter (Berman, P. W. et al., Science 222, 524-527 (1983)), the metallothionein promoter (Brinster, R. L. et al., Nature 296, 3942 (1982)), the heat shock promoter (Voellmy et al., PNAS USA 82, 494953 (1985)), the major late promoter of Ad2 and the .beta.-actin promoter (Tang et al., Nature 356, 152-154 (1992)). The regulatory sequences may also include terminator and poly-adenylation sequences. Amongst the sequences that can be used are the well known bovine growth hormone poly-adenylation sequence, the SV40 poly-adenylation sequence, the human cytomegalovirus terminator and poly-adenylation sequences.

Bacterial, yeast, fungal, insect and vertebrate cell expression systems are very frequently used systems. Such systems are well known in the art and generally available, e.g. commercially through Clontech Laboratories Inc. (4030 Fabian Way, Palo Alto, Calif. 94303-4607, USA). Next to these expression systems, parasite-based expression systems are attractive expression systems. Such systems are e.g. described in the French Patent Application with Publication number 2 714 074, and in US NTIS Publication No U.S. Ser. No. 08/043,109 (Hoffman, S, and Rogers, W.: Public. Date 1 Dec. 1993).

A very attractive expression system for heterologous nematode gene expression is a nematodal expression system based upon the worm Caenorrhabditis elegans. A heterologous expression system for this nematode has been described by Redmond, D. L. et al., in Molecular and Biochemical Parasitology 112, 125-131 (2001). See also Hashmi, S. et al., in Trends in Parasitology 17, 387-393 (2001).

The genes according to the present invention can be fused immediately downstream of a C. elegans cystein protease promoter, cpr-5, which has been shown recently to direct expression to the gut of C. elegans (Redmond et al., 2001) and cloned into the pGEX -vector. The slow growing DR96 unc76(e911) C. elegans mutant strain can be transformed by micro-injection of plasmid DNA into the distal arm of the hermaphrodite gonad. The plasmid DNA can e.g. be prepared using the Qiagen method. Ostertagia genes according to the invention can be coinjected with the repair plasmid p76-16B. The p7616B plasmid rescues the unc76 phenotype and allows transformants to be identified through reversion back to the wild type phenotype. Transformed lines in which the second and subsequent generations show the wild type phenotype will be maintained. The presence of the injected construct in transgenic worms can easily be verified by PCR analysis of single worms with primers developed specifically for the DNA of interest (Kwa et al., Journal of Molecular Biology 246, 500-510. (1995)). Transgenic worms, rescued by p76-16B, grow more quickly than the unc76(e911) mutants and allow rapid accumulation of transgenic worm material. Because of its rapid life-cycle, transformants can be grown in vitro in large quantities. Somatic extracts of transgenic worms can be prepared by grinding the nematodes in a mortar under liquid nitrogen and resuspending them in 0.05M PBS containing 2% TritonX-100.RTM.. Fusion proteins will be purified by affinity chromatography using a Glutathione Sepharose column.

A still even more preferred form of this embodiment of the invention relates to Live Recombinant Carriers (LRCs) comprising a nucleic acid sequence encoding an Ostertagia ostertagi protein or an immunogenic fragment thereof according to the invention, a DNA fragment according to the invention or a recombinant DNA molecule according to the invention. These LRCs are microorganisms or viruses in which additional genetic information, in this case a nucleic acid sequence encoding an Ostertagia ostertagi protein or an immunogenic fragment thereof according to the invention has been cloned. Cattle infected with such LRCs will produce an immunological response not only against the immunogens of the carrier, but also against the immunogenic parts of the protein(s) for which the genetic code is additionally cloned into the LRC, such as e.g. one or more of the novel Ostertagia ostertagi proteins gene according to the invention.

As an example of bacterial LRCS, attenuated Salmonella strains known in the art can very attractively be used.

Also, live recombinant carrier parasites have i.a. been described by Vermeulen, A. N. (Int. J. Parasitol. 28, 1121-1130 (1998)).

Furthermore, LRC viruses may be used as a way of transporting the nucleic add sequence into a target cell. Live recombinant carrier viruses are also called vector viruses. Viruses often used as vectors are Vaccinia viruses (Panicali et al; PNAS USA 79, 4927 (1982), Herpesviruses (E.P.A. 0473210A2), and Retroviruses (Valerio, D. et al.; in Baum, S. J., Dicke, K. A, Lotzova, E. and Pluznik, D. H. (Eds.), Experimental Haematology today-1988. Springer Verlag, New York: pp. 92-99 (1989)).

The technique of in vivo homologous recombination, well known in the art can be used to introduce a recombinant nucleic acid sequence into the genome of a bacterium, parasite or virus of choice, capable of inducing expression of the inserted nucleic acid sequence according to the invention in the host animal.

Finally another form of this embodiment of the invention relates to a host cell comprising a nucleic acid sequence encoding a protein according to the invention, a DNA fragment comprising such a nucleic add sequence or a recombinant DNA molecule comprising such a nucleic acid sequence under the control of a functionally linked promoter. This form also relates to a host cell containing a live recombinant carrier comprising a nucleic acid molecule encoding an Ostertagia ostertagi protein or an immunogenic fragment thereof according to the invention.

A host cell may be a cell of bacterial origin, e.g. Escherichia coli, Bacillus subtilis and Lactobacillus species, in combination with bacteria-based plasmids as pBR322, or bacterial expression vectors as the pEX-, pET-, pGEX-series, or with bacteriophages. The host cell may also be of eukaryotic origin, e.g. yeast-cells in combination with yeast-specific vector molecules, or higher eukaryotic cells like insect cells (Luckow et al.; Biotechnology 6, 47-55 (1988)) in combination with vectors or recombinant baculoviruses, plant cells in combination with e.g. Ti-plasmid based vectors or plant viral vectors (Barton, K. A. et al.; Cell 32, 1033 (1983), mammalian cells like Hela cells, Chinese Hamster Ovary cells (CHO) or Crandell-Rees Feline Kidney-cells, also with appropriate vectors or recombinant viruses.

Also, the host may be a nematode such as C. elegans, as explained above.

Another embodiment of the invention relates to the novel Ostertagia ostertagi proteins and to immunogenic fragments thereof according to the invention.

The concept of immunogenic fragments will be defined below.

One form of this embodiment relates to an Ostertagia ostetagi protein and to immunogenic fragments thereof, wherein the protein or immunogenic fragments have a sequence homology of at least 90%, preferably however 92%, more preferably 94%, 95% or even 96% homology, in that order or preference, to the amino acid sequence as depicted in SEQ ID NO: 8.

Even more preferred is a homology level of 97%, 98%, 99% or even 100% in that order of preference.

The immunogenic fragments of the Ostertagia ostertagi protein as depicted in SEQ ID NO: 2, 4, 6, 8, 10, 12 and 14 according to the invention as described herein, preferably have a length of at least 7, more preferably 10, 15, 20, 30 or even 40 amino adds, in that order of preference.

A still even more preferred form of this embodiment relates to this Ostertagia ostertagi protein and immunogenic fragments of said protein, encoded by a nucleic acid sequence according to the present invention.

Another form of this embodiment relates to a 28 kD Ostertagia ostertagi protein and to immunogenic fragments thereof wherein the protein or immunogenic fragments have a sequence homology of at least 90%, preferably however 92%, more preferably 94%, 95% or even 96% homology, in that order or preference, to the amino add sequence as depicted in SEQ ID NO: 4.

Even more preferred is a homology level of 97%, 98%, 99% or even 100% in that order of preference.

A still even more preferred form of this embodiment relates to a 28 kD Ostertagia ostertagi protein and immunogenic fragments of said protein, encoded by a nucleic acid sequence according to the present invention.

Still another form of this embodiment relates to a 25 kD Ostertagia ostertagi protein and to immunogenic fragments thereof, wherein the protein or immunogenic fragments have a sequence homology of at least 90%, preferably however 92%, more preferably 94%, 95% or even 96% homology, in that order or preference, to the amino acid sequence as depicted in SEQ ID NO: 6.

Even more preferred is a homology level of 97%, 98%, 99% or even 100% in that order of preference.

A still even more preferred form of this embodiment relates to a 25 kD Ostertagia ostertagi protein and immunogenic fragments of said protein, encoded by a nucleic acid sequence according to the present invention.

Again another form of this embodiment relates to a 31 kD Osteragia ostertagi protein and to immunogenic fragments thereof, wherein the protein or immunogenic fragments have a sequence homology of at least 90%, preferably however 92%, more preferably 94%, 95% or even 96% homology, in that order or preference, to the amino acid sequence as depicted in SEQ ID NO: 2.

Even more preferred is a homology level of 97%, 98%, 99% or even 100% in that order of preference.

A still even more preferred form of this embodiment relates to a 31 kD Ostertagia ostertagi protein and immunogenic fragments of said protein, encoded by a nucleic acid sequence according to the present invention.

One other form of this embodiment relates to a 30 kD Ostertagia ostertagi protein and to immunogenic fragments thereof, wherein the protein or immunogenic fragments have a sequence homology of at least 90%, preferably however 92%, more preferably 94%, 95% or even 96% homology, in that order or preference, to the amino acid sequence as depicted in SEQ ID NO: 10.

Even more preferred is a homology level of 97%, 98%, 99% or even 100% in that order of preference.

A still even more preferred form of this embodiment relates to a 30 kD Ostertagia ostertagi protein and immunogenic fragments of said protein, encoded by a nucleic acid sequence according to the present invention.

Again an other form of this embodiment relates to a 24 kD Ostertagia ostartagi protein and to immunogenic fragments thereof, wherein the protein or immunogenic fragments have a sequence homology of at least 90%, preferably however 92%, more preferably 94%, 95% or even 96% homology, in that order of preference, to the amino acid sequence as depicted in SEQ ID NO: 12.

Even more preferred is a homology level of 97%, 98%, 99% or even 100% in that order of preference.

A still even more preferred form of this embodiment relates to a 24 kD Ostertagia ostertagi protein and immunogenic fragments of said protein, encoded by a nucleic acid sequence according to the present invention.

Again another form of this embodiment relates to a 65 kD Ostertagia ostertagi protein and to immunogenic fragments thereof, wherein the protein or immunogenic fragments have a sequence homology of at least 90%, preferably however 92%, more preferably 94%, 95% or even 96% homology, in that order or preference, to the amino acid sequence as depicted in SEQ ID NO: 14.

Even more preferred is a homology level of 97%, 98%, 99% or even 100% in that order of preference.

A still even more preferred form of this embodiment relates to a 65 kD Ostertagia ostertagi protein and immunogenic fragments of said protein, encoded by a nucleic acid sequence according to the present invention.

The level of protein homology can be determined with the computer program "BLAST 2 SEQUENCES" by selecting subprogram: "BLASTP", that can be found at www.ncbi.nlm.nih.gov/blast/bl2seq/bl2.html.

A reference for this program is Tatiana A Tatusova, Thomas L. Madden, FEMS Microbiol. Letters 174, 247-250 (1999). Matrix used: "blosum62". Parameters used are the default parameters: Open gap: 11. Extension gap: 1. Gap x_dropoff: 50.

It will be understood that, for the particular proteins embraced herein, natural variations can exist between individual Ostertagia ostertagi strains. These variations may be demonstrated by (an) amino acid difference(s) in the overall sequence or by deletions, substitutions, insertions, inversions or additions of (an) amino acid(s) in said sequence. Amino acid substitutions which do not essentially alter biological and immunological activities, have been described, e.g. by Neurath et al in The Proteins, Academic Press New York (1979). Amino acid replacements between related amino acids or replacements which have occurred frequently in evolution are, inter alia, Ser/Ala, Ser/Gly, Asp/Gly, Asp/Asn, Ile/Val (see Dayhof, M. D., Atlas of protein sequence and structure, Nat. Biomed. Res. Found., Washington D.C. (1978), vol. 5, suppl. 3). Other amino acid substitutions include Asp/Glu, Thr/Ser, Ala/Gly, Ala/Thr, Ser/Asn, Ala/Val, Thr/Phe, Ala/Pro, Lys/Arg, Leu/Ile, Leu/Val and Ala/Glu. Based on this information, Lipman and Pearson developed a method for rapid and sensitive protein comparison (Science 227, 1435-1441 (1985)) and determining the functional similarity between homologous proteins. Such amino acid substitutions of the exemplary embodiments of this invention, as well as variations having deletions and/or insertions are within the scope of the invention as long as the resulting proteins retain their immune reactivity.

This explains why Ostertagia ostertagi proteins according to the invention, when isolated from different field isolates, may have homology levels of about 70%, while still representing the same protein with the same immunological characteristics.

Those variations in the amino acid sequence of a certain protein according to the invention that still provide a protein capable of inducing an immune response against infection with Ostertagia ostertagi or at least against the clinical manifestations of the infection are considered as "not essentially influencing the immunogenicity".

When a protein is used for e.g. vaccination purposes or for raising antibodies, it is however not necessary to use the whole protein. It is also possible to use a fragment of that protein that is capable, as such or coupled to a carrier such as e.g. KLH, of inducing an immune response against that protein, a so-called immunogenic fragment. An "immunogenic fragment" is understood to be a fragment of the full-length protein that still has retained its capability to induce an immune response in a vertebrate host, e.g. comprises a B- or T-cell epitope. Shortly, an immunogenic fragment is a fragment that is capable of inducing an antigenic response against an Ostertagia ostertagi protein according to the invention. At this moment, a variety of techniques are available to easily identify DNA fragments encoding antigenic fragments (determinants). The method described by Geysen et al., (Patent Application WO 84/03564, Patent Application WO 86/06487, U.S. Pat. No. 4,833,092, PNAS USA 81, 3998-4002 (1984), J. Imm. Meth. 102, 259-274 (1987), the so-called PEPSCAN method is an easy to perform, quick and well-established method for the detection of epitopes; the immunologically important regions of the protein. The method is used worldwide and as such well known to man skilled in the art. This (empirical) method is especially suitable for the detection of B-cell epitopes. Also, given the sequence of the gene encoding any protein, computer algorithms are able to designate specific protein fragments as the immunologically important epitopes on the basis of their sequential and/or structural agreement with epitopes that are now known. The determination of these regions is based on a combination of the hydrophilicity criteria according to Hopp and Woods (PNAS USA 78, 38248-3828 (1981)), and the secondary structure aspects according to Chou and Fasman (Advances in Enzymology 47, 45-148 (1987) and U.S. Pat. No. 4,554,101). T-cell epitopes can likewise be predicted from the sequence by computer with the aid of Berzofsky's amphiphilicity criterion (Science 235, 1059-1062 (1987) and US Patent application NTIS U.S. Ser. No. 07/005,885). A condensed overview is found in: Shan Lu, on common principles: Tibtech 9, 238-242 (1991); Good et al., on Malaria epitopes: Science 235, 1059-1062 (1987); Lu, for a review: Vaccine 10, 3-7 (1992); and Berzofsky, for HIV-epitopes: The FASEB Journal 5, 2412-2418 (1991). An immunogenic fragment usually has a minimal length of 6, more commonly 7-8 amino acids, preferably more then 8, such as 9, 10, 12, 15 or even 20 or more amino acids. The nucleic acid sequences encoding such a fragment therefore have a length of at least 18, more commonly 24 and preferably 27, 30, 36, 45 or even 60 nucleic acids.

Therefore, one form of still another embodiment of the invention relates to vaccines for combating Ostertagia ostertagi infection, that comprise at least one Ostertagia ostertagi protein or immunogenic fragments thereof, according to the invention as described above together with a pharmaceutically acceptable carrier.

Still another embodiment of the present invention relates to the Ostertagia ostertagi proteins according to the invention or immunogenic fragments thereof for use in a vaccine.

Again another embodiment of the present invention relates to the use of a nucleic acid sequence, a DNA fragment, a recombinant DNA molecule, a live recombinant carrier, a host cell or a protein or an immunogenic fragment thereof according to the invention for the manufacturing of a vaccine, more specifically a vaccine for combating Ostertagia ostertagi infection.

One way of making a vaccine according to the invention is by growing the nematode, followed by biochemical purification of an Ostertagia ostertagi protein or immunogenic fragments thereof, from the nematode or the supernatant. This is however a very time-consuming way of making the vaccine.

It is therefore much more convenient to use the expression products of a gene encoding an Ostertagia ostertagi protein or immunogenic fragments thereof, according to the invention in vaccines. This is possible for the first time now because the nucleic acid sequences of genes encoding 7 novel Ostertagia ostertagi proteins suitable as vaccine components is provided in the present invention.

Vaccines based upon the expression products of these genes can easily be made by admixing the protein according to the invention or immunogenic fragments thereof according to the invention with a pharmaceutically acceptable carrier as described below.

Alternatively, a vaccine according to the invention can comprise live recombinant carriers as described above, capable of expressing the protein according to the invention or immunogenic fragments thereof. Such vaccines, e.g. based upon a Salmonella carrier or a viral carrier e.g. a Herpesvirus vector have the advantage over subunit vaccines that they better mimic the natural way of infection of Ostertagia ostertagi. Moreover, their self-propagation is an advantage since only low amounts of the recombinant carrier are necessary for immunization.

Vaccines can also be based upon host cells as described above that comprise the protein or immunogenic fragments thereof according to the invention.

All vaccines described above contribute to active vaccination, i.e. they trigger the host's defense system.

Alternatively, antibodies can be raised in e.g. rabbits or can be obtained from antibody -producing cell lines as described below. Such antibodies can then be administered to the cow. This method of vaccination, passive vaccination, is the vaccination of choice when an animal is already infected, and there is no time to allow the natural immune response to be triggered. It is also the preferred method for vaccinating animals that are prone to sudden high infection pressure. The administered antibodies against the protein according to the invention or immunogenic fragments thereof can in these cases interfere with Ostertagia ostertagi. This approach has the advantage that it decreases or stops Ostertagia ostertagi development.

Therefore, one other form of this embodiment of the invention relates to a vaccine for combating Ostertagia ostertagi infection that comprises antibodies against an Ostertagia ostertagi protein according to the invention or an immunogenic fragment of that protein, and a pharmaceutically acceptable carrier.

Still another embodiment of this invention relates to antibodies against an Ostertagia ostertagi protein according to the invention or an immunogenic fragment of that protein.

Methods for large-scale production of antibodies according to the invention are also known in the art. Such methods rely on the cloning of (fragments of) the genetic information encoding the protein according to the invention in a filamentous phage for phage display. Such techniques are described i.a. at the "Antibody Engineering Page" under "Filamentous phage display" at http://aximt1.imt.uni-marburg.de/.about.rek/aepphage.html., and in review papers by Cortese, R. et al., (1994) in Trends in Biotechn. 12, 262-267., by Clackson, T. & Wells, J. A. (1994) in Trends in Biotechn. 12, 173-183, by Marks, J. D. et al., (1992) in J. Biol Chem. 267, 16007-16010, by Winter, G. et al., (1994) in Annu. Rev. Immunol. 12, 433-455, and by Little, M. et al., (1994) Biotechn. Adv. 12, 539-555. The phages are subsequently used to screen camelid expression libraries expressing camelid heavy chain antibodies. (Muyldennans, S, and Lauwereys, M., Journ. Molec. Recogn. 12, 131-140 (1999) and Ghahroudi, M. A. et al., FEBS Letters 414, 512-526 (1997)). Cells from the library that express the desired antibodies can be replicated and subsequently be used for large-scale expression of antibodies.

Still another embodiment relates to a method for the preparation of a vaccine according to the invention that comprises the admixing of antibodies according to the invention and a pharmaceutically acceptable carrier.

An alternative and efficient way of vaccination is direct vaccination with DNA encoding the relevant antigen. Direct vaccination with DNA encoding proteins has been successful for many different proteins. (As reviewed in e.g. Donnelly et al., The Immunologist 2, 20-26 (1993)). In the field of anti-parasite vaccines, protection against e.g. Plasmodium yoelii has been obtained with DNA-vaccination with the Plasmodium yoelii circumsporozoite gene (Vaccine 12, 1529-1533 (1994)). Protection against Leishmania major has been obtained with DNA-vaccination with the Leishmania major surface glycoprotein gp83 gene (Vaccine 12, 1534-1536 (1994)).

This way of vaccination is also attractive for the vaccination of cattle against Ostertagia ostertagi infection. Therefore, still other forms of this embodiment of the invention relate to vaccines comprising nucleic acid sequences encoding a protein according to the invention or immunogenic fragments thereof, vaccines comprising DNA fragments that comprise such nucleic acid sequences or vaccines comprising recombinant DNA molecules according to the invention, and a pharmaceutically acceptable carrier.

Examples of DNA plasmids that are suitable for use in a DNA vaccine according to the invention are conventional cloning or expression plasmids for bacterial, eukaryotic and yeast host cells, many of said plasmids being commercially available. Well-known examples of such plasmids are pBR322 and pcDNA3 (Invitrogen). The DNA fragments or recombinant DNA molecules according to the invention should be able to induce protein expression of the nucleotide sequences. The DNA fragments or recombinant DNA molecules may comprise one or more nucleotide sequences according to the invention. In addition, the DNA fragments or recombinant DNA molecules may comprise other nucleotide sequences such as immune-stimulating oligonucleotides having unmethylated CpG di-nucleotides, or nucleotide sequences that code for other antigenic proteins or adjuvating cytokines.

The nucleotide sequence according to the present invention or the DNA plasmid comprising a nucleotide sequence according to the present invention, preferably operably linked to a transcriptional regulatory sequence, to be used in the vaccine according to the Invention can be naked or can be packaged in a delivery system. Suitable delivery systems are lipid vesicles, ISCOMs.RTM., dendromers, niosomes, microparticles, especially chitosan-based microparticles, polysaccharide matrices and the like, (see further below) all well-known in the art. Also very suitable as delivery system are attenuated live bacteria such as Salmonella species, and attenuated live viruses such as Herpesvirus vectors, as mentioned above.

Still other forms of this embodiment relate to vaccines comprising recombinant DNA molecules according to the invention.

DNA vaccines can e.g. easily be administered through intradermal application such as by using a needle-less injector. This way of administration delivers the DNA directly into the cells of the animal to be vaccinated. Amounts of DNA in the range between 10 pg and 1000 .mu.g provide good results. Especially if the DNA is self-replicating, minor amounts will suffice. Preferably, amounts in the microgram range between 1 and 100 .mu.g are used.

In a further embodiment, the vaccine according to the present invention additionally comprises one or more antigens derived from cattle pathogenic organisms and viruses, antibodies against those antigens or genetic information encoding such antigens and/or a pharmaceutical component such as an antibiotic.

Of course, such antigens, antibodies against such antigens, or genetic information can be of Ostertagia ostertagi origin, such as e.g. another Ostertagia ostertagi antigen. It can also be an antigen, antibodies or genetic information selected from another cow pathogenic organism or virus. Such organisms and viruses are preferably selected from the group of Bovine Herpesvirus, Bovine Viral Diarrhea virus, Parainfluenza type 3 virus, Bovine Paramyxovirus, Foot and Mouth Disease virus, Pasteurella haemolytica, Bovine Respiratory Syncytial Virus, Thelleria sp., Babesia sp., Trypanosoma sP.T Anaplasma sp., Neospora caninum, Staphylococcus aureus, Streptococcus agalactiae, Mycoplasma, E. coli, Enterobacter, Kiebsiella, Citobacter, Cryptosporidium, Salmonella and Streptococcus dysgalactiae.

Vaccines based upon one or more of the Ostertagia ostertagi proteins according to the invention are also very suitable as marker vaccines. A marker vaccine is a vaccine that allows to discriminate between vaccinated and field-infected cows e.g. on the basis of a characteristic antibody panel, different from the antibody panel induced by wild type infection. A different antibody panel is induced e.g. when an immunogenic protein present on a wild type Ostertagia is not present in a vaccine: the host will then not make antibodies against that protein after vaccination. Thus, a vaccine based upon any of the Ostertagia ostertagi proteins according to the invention would only induce antibodies against that specific protein, whereas a vaccine based upon a live wild-type, live attenuated or inactivated whole Ostertagia ostertagi would induce antibodies against all or most of the nematodal proteins.

A simple ELISA test, having wells comprising any other Ostertagia protein except for the Ostertagia ostertagi proteins according to the present invention and wells comprising only one or more purified Ostertagia ostertagi proteins according to the invention suffices to test serum from cows and to tell if the cows are either vaccinated with the protein vaccine according to the invention or suffered from Ostertagia ostertagi field infection.

All vaccines according to the present invention comprise a pharmaceutically acceptable carrier. A pharmaceutically acceptable carrier can be e.g. sterile water or a sterile physiological salt solution. In a more complex form the carrier can e.g. be a buffer.

Methods for the preparation of a vaccine comprise the admixing of a protein or an immunogenic fragment thereof, according to the invention and/or antibodies against that protein or an immunogenic fragment thereof, and/or a nucleic acid sequence and/or a DNA fragment, a recombinant DNA molecule, a live recombinant carrier or host cell according to the invention, and a pharmaceutically acceptable carrier.

Vaccines according to the present invention may in a preferred presentation also contain an immunostimulatory substance, a so-called adjuvant. Adjuvants in general comprise substances that boost the immune response of the host in a non-specific manner. A number of different adjuvants are known in the art. Examples of adjuvants frequently used in cow vaccines are muramyldipeptides, lipopolysacharides, several glucans and glycans and Carbopol.RTM. (a homopolymer).

The vaccine may also comprise a so-called "vehicle". A vehicle is a compound to which the protein adheres, without being covalently bound to it. Such vehicles are i.a. bio -microcapsules, micro-alginates, liposomes and macrosols, all known in the art. Microparticles, more specifically those based upon chitosan, especially for use in oral vaccination are very suitable as vaccine vehicles.

A special form of such a vehicle, in which the antigen is partially embedded in the vehicle, is the so-called ISCOM.RTM. (EP 109.942, EP 180.564, EP 242.380)

In addition, the vaccine may comprise one or more suitable surface-active compounds or emulsifiers, e.g. Span.RTM. or Tween.RTM..

Antigens will preferably be combined with adjuvants that are readily available and that are registered for use in domestic animals, e.g. aluminum hydroxide, a Th2-like modulating adjuvant.

Two alternative approaches for antigen delivery are especially suitable for application of the vaccines according to the present invention: a. systemic immunization with the inclusion of adjuvantia modulating immune responses towards the mucosa, such as vitamin D3 (Van der Stede, Y., et al., Vaccine 19, 1870-1878 (2001)) or QuilA.RTM., and b. direct delivery to the respiratory mucosa by inhalation of naked DNA (plasmid) (Vanrompay, D., et al., Immunology 103, 106-112 (2001)).

Addition of CpG oligonucleotide sequences inside or outside the plasmid is also preferred for improving protection (Van der Stede, Y., et al., Vet Immunol. Immunopathol., 86, 31-41 (2002).

Often, the vaccine is mixed with stabilizers, e.g. to protect degradation-prone proteins from being degraded, to enhance the shelf-life of the vaccine, or to improve freeze-drying efficiency. Useful stabilizers are i.a. SPGA (Bovarnik et al; J. Bacteriology 59, 509 (1950)), carbohydrates e.g. sorbitol, mannitol, trehalose, starch, sucrose, dextran or glucose, proteins such as albumin or casein or degradation products thereof, and buffers, such as alkali metal phosphates.

In addition, the vaccine may be suspended in a physiologically acceptable diluent. It goes without saying, that other ways of adjuvating, adding vehicle compounds or diluents, emulsifying or stabilizing a protein are also embodied in the present invention.

Vaccines according to the invention that are based upon the protein according to the invention or immunogenic fragments thereof can very suitably be administered in amounts ranging between 1 and 100 micrograms of protein per animal, although smaller doses can in principle be used. A dose exceeding 100 micrograms will, although immunologically very suitable, be less attractive for commercial reasons.

Vaccines based upon live attenuated recombinant carriers, such as the LRC-viruses, parasites and bacteria described above can be administered in much lower doses, because they multiply themselves during the infection. Therefore, very suitable amounts would range between 10.sup.3 and 10.sup.9 CFU/PFU for both bacteria and viruses.

Vaccines according to the invention can be administered e.g. intradermally, subcutaneously, intramuscularly, intraperitoneally, intravenously, or at mucosal surfaces such as orally or intranasally.

For efficient protection against disease, a quick and correct diagnosis of Ostertagia ostertagi infection is important.

Therefore it is another objective of this invention to provide diagnostic tools suitable for the detection of Ostertagia ostertagi infection.

The nucleic acid sequences, the proteins and the antibodies according to the invention are also suitable for use in diagnostics.

Therefore, another embodiment of the invention relates to nucleic acid sequences, proteins and antibodies according to the invention for use in diagnostics.

The nucleic acid sequences or fragments thereof according to the invention can be used to detect the presence of Ostertagia ostertagi in cows. A sample taken from the abomasums of cows infected with Ostertagia ostertagi will comprise nucleic acid material derived from said parasite, including nucleic add sequences encoding for the protein according to the invention. These nucleic add sequences will hybridize with a nucleic acid sequence according to the invention. Suitable methods for the detection of nucleic acid sequences that are reactive with the nucleic acid sequences of the present invention include hybridization techniques including but not limited to PCR techniques and NASBA.RTM. techniques. Thus the nucleic acid sequences according to the invention can be used to prepare probes and primers for use in PCR and or NASBA techniques.

A diagnostic test kit for the detection of Ostertagia ostertagi may e.g. comprise tools to enable the reaction of Ostertagia nucleic acid isolated from the cows to be tested with these tools. Such tools are e.g. specific probes or (PCR-) primers, also referred to as primer fragments, based upon the nucleic add sequences according to the invention. If genetic material of Ostertagia ostertagi is present in the animal, this will e.g. specifically bind to specific PCR-primers and, e.g. after cDNA synthesis, will subsequently become amplified in PCR-reaction. The PCR-reaction product can then easily be detected in DNA gel electrophoresis.

Standard PCR-textbooks give methods for determining the length of the primers for selective PCR-reactions with Ostertagia ostertagi DNA. Primer fragments with a nucleotide sequence of at least 12 nucleotides are frequently used, but primers of more than 15, more preferably 18 nucleotides are somewhat more selective. Especially primers with a length of at least 20, preferably at least 30 nucleotides are very generally applicable. PCR-techniques are extensively described in C. Dieffenbach & G. Dveksler: PCR primers: a laboratory manual, CSHL Press, ISBN 879694473 (1995)).

Nucleic add sequences according to the invention or primers of those nucleic acid sequences having a length of at least 12, preferably 15, more preferably 18, even more preferably 20, 22, 25, 30, 35 or 40 nucleotides in that order of preference, wherein the nucleic acid sequences or parts thereof have at least 70% homology with the nucleic acid sequence as depicted in SEQ ID NO: 1, 3, 5, 7, 9, 11 or 13 are therefore also part of the invention. Primers are understood to have a length of at least 12 nucleotides and a homology of at least 70%, more preferably 80%, 85%, 90%, 95%, 98%, 99% or even 100%, in that order of preference, with the nucleic add sequence as depicted in SEQ ID NO: 1, 3, 5, 7, 9, 11 or 13. Such nucleic acid sequences can be used as primer fragments in PCR-reactions in order to enhance the amount of DNA that they encode or in hybridization reactions. This allows the quick amplification or detection on blots of specific nucleotide sequences for use as a diagnostic tool for e.g. the detection of Ostertagia ostertagi as indicated above.

Another test on genetic material is based upon Ostertagia material obtained from e.g. a swab, followed by classical DNA purification followed by classical hybridization with radioactively or color-labeled primer fragments. Colour-labelled and radioactively labeled fragments are generally called detection means. Both PCR-reactions and hybridization reactions are well-known in the art and are i.a. described in Sambrook & Russell, supra

Thus, one embodiment of the invention relates to a diagnostic test kit for the detection of Ostertagia ostertagi nucleic acid sequences. Such a test comprises a nucleic acid sequence according to the invention or a primer fragment thereof.

A diagnostic test kit based upon the detection of antigenic material of the specific Ostertagia ostertagi proteins according to the invention and therefore suitable for the detection of Ostertagia ostertagi infection may i.a. comprise a standard ELISA test. In one example of such a test the walls of the wells of an ELISA plate are coated with antibodies directed against any of the proteins according to the invention. After incubation with the material to be tested, labeled anti-Ostertagia ostertagi antibodies are added to the wells. A color reaction then reveals the presence of antigenic material from Ostertagia ostertagi. Therefore, still another embodiment of the present invention relates to diagnostic test kits for the detection of antigenic material of Ostertagia ostertagi. Such test kits comprise antibodies against a protein according to the invention or a fragment thereof according to the invention.

A diagnostic test kit based upon the detection in serum of antibodies against a protein of Ostertagia ostertagi according to the invention and therefore suitable for the detection of Ostertagia ostertagi infection may i.a. comprise a standard ELISA test. In such a test the walls of the wells of an ELISA plate can e.g. be coated with an Ostertagia ostertagi protein according to the invention. After incubation with the material to be tested, labeled anti-bodies against that protein are added to the wells. A color reaction then reveals the presence of antibodies against Ostertagia ostertagi.

Therefore, still another embodiment of the present invention relates to diagnostic test kits for the detection of antibodies against Ostertagia ostertagi. Such test kits comprise an Ostertagia ostertagi protein according to the invention or a fragment thereof according to the invention.

The design of the immunoassay may vary. For example, the immunoassay may be based upon competition or direct reaction. Furthermore, protocols may use solid supports or may use cellular material. The detection of the antibody-antigen complex may involve the use of labeled antibodies; the labels may be, for example, enzymes, fluorescent-, chemoluminescent-, radio-active- or dye molecules.

Suitable methods for the detection of antibodies reactive with a protein according to the present invention in the sample include the enzyme-linked immunosorbent assay (ELISA), immunofluorescense test (IFT) and Western blot analyses.

The proteins or immunogenic fragments thereof according to the invention e.g. expressed as indicated above can be used to produce antibodies, which may be polyclonal, monospecific or monoclonal (or derivatives thereof). If polyclonal antibodies are desired, techniques for producing and processing polyclonal sera are well known in the art (e.g. Mayer and Walter, eds. Immunochemical Methods in Cell and Molecular Biology, Academic Press, London (1987)).

Monoclonal antibodies, reactive against the protein according to the invention or an immunogenic fragment thereof according to the present invention, can be prepared by immunizing inbred mice by techniques also known in the art (Kohler and Milstein, Nature, 256, 49S-497 (1975)).
 

Claim 1 of 6 Claims

1. An isolated 31 kD Ostertagia ostertagi protein, wherein said protein has the sequence of SEQ ID NO: 2.
 

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